I married a widow who had a grown up daughter. My father visited us often, fell in love with my step-daughter and married her. Thus he became my son-in-law, and my step daughter became my mother, because she was my fathers wife.
Soon after this my wife gave birth to a son, which of course was my father's son-in law and my uncle for he was the brother of my mother.
My father's wife also became the mother of a son. He was of course my brother and also my grandchild, for he was the son of my step-daughter.
Accordingly , my wife was my grandmother, because she was my mother's mother. I was my wife's husband and grandchild at once, and as the husband of a person's grandmother is his grandfather..
I BECAME MY OWN GRANDFATHER!